1. Field of the Invention
The present invention relates to a liquid crystal display with a plurality of openings (slits) formed on an electrode.
2. Description of the Background Art
As an information display device, a display device with extremely low display brightness of the background display area or the dark display area is demanded, and a vertical alignment liquid crystal display is known as a display device capable of realizing the same. A vertical alignment liquid crystal display is able to achieve extremely low transmissivity in the initial oriented state since the optical characteristics during the front face observation in the initial oriented state are approximately equal to the optical characteristics in a polarizing plane of a crossed nicols arrangement.
With the foregoing vertical alignment liquid crystal display, in order to obtain favorable viewing-angle characteristics even during voltage application, it is effective to separate the orientation direction of the liquid crystal molecules into a plurality of directions in one pixel (multi-domain orientation), and various types of technologies have been proposed for realizing the same. For example, Japanese Patent No. 4107978 (Patent Document 1) discloses an electrode structure for realizing the foregoing multi-domain orientation in a segment display-type liquid crystal display. With this liquid crystal display, the upper and lower electrodes placed opposite each other are respectively provided with elongated rectangular openings, and the upper and lower electrodes are arranged so that the openings of the upper electrode and the openings of the lower electrode are alternately aligned in the planar view. Since it is thereby possible to generate a diagonal electric field around the respective openings, the orientation direction of the liquid crystal molecules can be rotated 180° with the opening as the boundary. Patent Document 1 discloses a liquid crystal display in which rectangular openings are alternately arranged on the opposed upper and lower substrates as an effective electrode structure even for an arbitrary display pattern upon mainly performing a character (segment) display pattern.
With a liquid crystal display provided with numerous rectangular openings described above, depending on the layout of the openings, the orientation of the liquid crystal molecules may become uneven, and there are cases where problems such as deterioration in the effective aperture ratio or deterioration in the response speed during voltage application may occur. As one solution to the foregoing problems, Japanese Published Unexamined Patent Application No. 2009-122271 (Patent Document 2) discloses technology of causing the mutual distance of two openings which are adjacent in the longitudinal direction to be shorter than the length (slit width) of the respective openings in the lateral direction with respect to a plurality of rectangular openings provided on a substrate. According to the foregoing technology, it is possible to resolve problems caused by unevenness of in-plane etching or the like upon forming the respective openings by performing patterning treatment to the electrode.
Meanwhile, with the method proposed in Patent Document 2, if the length of the openings in the lateral direction is to be further shortened, it is necessary to consequently shorten the mutual distance of the foregoing openings in the longitudinal direction. However, if the mutual distance of the openings in the longitudinal direction is set to be shorter, there are cases where the adjacent openings become connected depending on the patterning treatment conditions; for example, based on the over-etching conditions. If this kind of connection of openings occurs frequently, it will incur a rise in the resistance value of the electrode, and there is concern that the display quality will deteriorate. Moreover, if all openings adjacent in the longitudinal direction become connected, it will incur the disconnection of the electrode, and there is concern that a display defect will occur and that the display quality will deteriorate.
As a specific mode of the present invention, an object of this invention is to provide technology capable of avoiding deterioration of the display quality in a liquid crystal display in which a plurality of openings are formed on an electrode.